Cooling-assist friction stir welding: A case study on AA6068 aluminum alloy and copper joint

Abstract

This study evaluates the impact of cooling-assist friction stir welding (CA-FSW) tool rotational and traverse velocities on the bonding quality of Al-Cu-Mg and copper lap joints. A modified computational fluid dynamics (CFD) technique analyzes heat generation and distribution during dissimilar CA-FSW joints between AA6068 alloy and copper. The relationship between CA-FSW tool velocities and metallurgical properties of the final joint is assessed. Simulation results provide insights into metallurgical phenomena during the CA-FSW process. Findings reveal greater plastic deformation and heat generation on the AA6068 aluminum alloy side due to raw material placement, resulting in more significant microstructure changes in AA6068 aluminum alloy compared to copper. Increased heat generation leads to higher copper-rich intermetallic compound (IMC) formation, resulting in increased hardness of the stir zone at the base metals’ interface.